5480
Member Since: 12 Sep 2006
Location: Luxembourg
Posts: 3
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| Discovery 3 more secure than Volvo XC90? |
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Someone argued somewhere in this forum that "for every 100kg in weight difference of the other contact vehicle though the risk of death or injury stats NCAP use should be adjusted by 7%".
Is there any scientific evidence for this statement or is it just someone's personal opinion?
So work it out :
Discovery 3...2500KG (31 points in NCAP)
Volvo XC90...2070KG (35 points in NCAP)
If correct, can one assume that that Volvo results must be adjusted by 7% for every 100kg?
If so, 4.3 X 7% = 30.1%, i.e. Volvo's 35 points must be reduced by 30.1% = 24 points (vs. Discovery's 31 points).
Any views?
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 13th Sep 2006 5:22 pm |
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DG
Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50934
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This statement was made by me I do believe .......and yes it is fact.
If you read this report from the NCAP site over the next few bedtimes all will be revealed 
http://www.euroncap.com/content/test_proce...?area_ID=4 21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
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| 13th Sep 2006 5:51 pm |
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DG
Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50934
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BTW the D3 they tested had a kerb weight of 2637kgs 21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
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| 13th Sep 2006 5:55 pm |
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DG
Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50934
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| Re: Discovery 3 more secure than Volvo XC90? |
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5480 wrote:If correct, can one assume that that Volvo results must be adjusted by 7% for every 100kg?
If so, 4.3 X 7% = 30.1%, i.e. Volvo's 35 points must be reduced by 30.1% = 24 points (vs. Discovery's 31 points).
Not sure it quite works like this though...it's the data in their stats that would be adjusted not the point score as such 21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
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| 13th Sep 2006 6:19 pm |
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OffRoader
Member Since: 23 Aug 2005
Location: North Extreme
Posts: 120
  
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| D3 is 91 % safer than average 4 star car ! |
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from that Swedish study:
" Crash testing into a fixed barrier is equivalent to a crash into a car of the same mass, while the real life outcome integrates weight as a factor influencing impact severity. In order to completely remove mass effects from the analysis, thereby allowing direct comparisons with barrier crash tests, it is possible to compensate for mass for the case vehicles as well. The same mass compensation factor was used (7% per 100kg)"
"If there is a weight difference between case vehicle and opponent vehicle, both vehicle types will be exposed to impact severity that differs from when the two groups of vehicles have the same weight (Fig. 2). If the case vehicle is lighter than the average vehicle it will have a higher change of velocity compared to the average vehicle. At the same time the opponent vehicle will have a lower change of velocity. The mass has therefore a double effect on the relative risk. While it might be desired to take into account the importance of weight for the case vehicle, the altered impact severity distribution must be compensated for relating to the opponent vehicle in order to allow comparisons with other case vehicles. Analysing how a defined set of vehicles was affected by varying mass relations derived the weight/change of velocity compensation. It was found that the risk of any injury as well as severe and fatal injury was increased or decreased by 7% for every 100-kg difference from the average weight. "
" The importance of weight should not be underestimated, and while this factor is not taken into account in crash tests into fixed barriers, 100kg more weight in a car to car impact will generate a 7% lower risk of injury. In single vehicle crashes, which account for a high proportion of crashes, the mass should not have any significant influence on safety."
Average mass of 4 star car is 1362 kg. Discovery 3 is 1300 heavier than the average 4 star car, meaning 13 * 7 = 91 % lower risk of injury !
Stars R1 Severe and fatal injuries R1 All injuries Avg. mass case (kg)No class 0,92 0,99 1332
2 0,92 1,10 1260
3 0,61 0,91 1450
4 0,65 0,96 1362 -- too many modifications made to my Disco 3 to be listed in here --
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| 13th Sep 2006 7:57 pm |
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DG
Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50934
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Thats how I read it too 21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
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| 13th Sep 2006 8:01 pm |
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oliver77
Member Since: 23 Jun 2006
Location: Mid Wales
Posts: 398
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It's a little more complicated that this. You have to take the absorbtion of kinetic energy into the equation(deformation patterns). A tank will probably have a kerb weight of 15000kgs but hit a non-deformable barrier in one of those at 40mph and you would probably be killed or at least very seriously injured.
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| 13th Sep 2006 8:24 pm |
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DiscoStu
Member Since: 09 Apr 2006
Location: London
Posts: 11412
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Surely the point is that there aren't many non-deformable barriers to a 15000kg tank? It's weight is part of its defence. Disco 5 HSE Lux
https://www.youtube.com/watch?v=peyiqaJrmMU
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| 13th Sep 2006 8:27 pm |
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oliver77
Member Since: 23 Jun 2006
Location: Mid Wales
Posts: 398
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I would be thinking of something like a rock face which wouldn't budge.
In theory there are non-deformable structures. When your car decelerates quickly so do you and everything in your car, if your car doesn't deform well then you decelerate quickly causing internal injuries.
I'm not arguing against the D3, as I have said before, this is my job and I choose a D3 so it can't be bad.
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| 13th Sep 2006 8:56 pm |
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Jamo
Member Since: 18 Jan 2006
Location: Esperance, Western Australia
Posts: 1170
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Actually a tank would have a weight of around 40,000kg to 60,000kg.
The barrier wouldn't be a problem. Before you got to it, it would simply be a case of saying "HESH barrier on" "loaded" "Fire" "Firing now" "target"; sipping some port and continuing on! Have a nice day!
2010 Cayenne Diesel with PASM & Off Road Pkg
2005 HSE D3 (Sold)
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| 13th Sep 2006 10:46 pm |
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DG
Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50934
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Thankfully we are not likely to encounter a tank...I hope  But Whilst I agree it's not that simple Jo... I think we can all see what the report is saying.... and in the main that interpretaion would apply during an unfortunate event 21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
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| 13th Sep 2006 10:59 pm |
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Gareth
Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26702
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Quote:Thankfully we are not likely to encounter a tank...I hope
You did'nt come to Salisbury then, plenty of Tanks around there.
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| 13th Sep 2006 11:11 pm |
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oliver77
Member Since: 23 Jun 2006
Location: Mid Wales
Posts: 398
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and the moral of the story........
Drive something big and heavy - hit something small and light
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| 14th Sep 2006 8:51 am |
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dflo
Member Since: 04 Jul 2006
Location: Wading in and out of it...
Posts: 1361
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oliver77 wrote:and the moral of the story........
Drive something big and heavy - hit something small and light
Yep... That about sums it up for me -  "Funny, mine doesn't do that......."
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| 14th Sep 2006 9:01 am |
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